PROJECT SUMMARY (See instructions); Although state-of-the-art CT provides accurate sub-millimeter details of the size and location of renal stones and separation of uric acid and non-uric acid stones, current routine clinical image analysis does not provide a comprehensive tool to quantitatively assess stone composition, volume, morphology and fragility, or to detect precursor lesions and trace elements related to stone formation. We have demonstrated that the novel algorithms developed in our lab during the initial funding period of our first O'Brien Center grant are able to separate eight common types of renal stones into five groups in an anthropomorphic phantom under clinical conditions, and into four groups in patients. In patients, we demonstrated an overall accuracy of 79.1%. We have also demonstrated the ability to accurately measure stone volume and surface morphology. In Project 1 of the current proposal, we will develop and validate tools to quantify interior stone morphology and use our quantitative measurements of stone composition, volume, surface and interior morphology to predict stone fragility. Thus, CT imaging, which is the predominant clinical tool used to diagnose and stage renal stones, can provide a much richer source of important clinical and research information when dual-energy data are acquired and quantitative analysis techniques used. The Imaging Core will provide five key functions in support of this O'Brien Urology Cooperative Research Center. These functions will directly support Projects 1, 2, and 3, and may be of value for pilot projects initiated during later years of the Center's activities. Additionally, the functions may be of considerable value to extramural researchers in the field of nephrolithiasis, including 1) Dual-energy CT scanning of ex-vivo specimens or patients; 2) Dual-energy CT attenuation, volume and morphology analyses; 3) Spectral CT scanning of ex-vivo specimens; 4) Coordination of micro-CT scanning and fragility testing with Dr. Jim Williams; and 5) Coordination of neutron activation analysis with Dr. Xin Liu.